1. Field of the Invention
The present invention relates to an optical modulator holder, an optical device, and to a projector.
2. Description of Related Art
There has been known a projector comprising a plurality of optical modulator devices each for forming an optical image by modulating a light beam irradiated from a light source according to image information, a color-combining optical device for combining light beams modulated by the optical modulator devices, and a projecting optical device for extending and projecting the light beam combined by the color-combining optical device.
Of the devices described above, as the optical modulator device, for instance, generally an optical modulator based on the active matrix driving system with an electrochemical optical material such as a liquid crystal sealed between a pair of substrates is employed. More specifically, the pair of substrate each constituting this optical modulator comprises a driving substrate provided in the light beam irradiation-side with a data line for loading a driving voltage to the liquid crystal, a scanning line, a switching element, a pixel electrode and the like formed thereon, and a counter substrate provided in the light beam incident-side with a common electrode, a black mask and the like formed thereon.
Further an incident-side polarization plate and an irradiation-side polarization plate allowing passage of light beam each having a specific polarization axis are provided in the light beam incident-side and the light beam irradiation-side of this optical modulator respectively.
When a light beam irradiated from a light source is irradiated onto an optical modulator, a temperature of the optical modulator will easily rise due to absorption of light by the liquid crystal layer as well as to absorption of light by a data line and a scanning line formed on the driving substrate, a black matrix formed on the counter substrate and the like. Further of the light beam irradiated from a light source and that having passed through the optical modulator, that having no specific polarization axis is easily absorbed by the incident-side polarization plate and the irradiation-side polarization plate, which often generates heat on the polarization plates.
As described above, for the projector having the optical element as described above, there has been proposed the configuration comprising a cooling device using a cooling fluid for moderate the rise of temperature in the optical element (Refer to, for instance, Japanese Patent Laid-Open Publication No. HEI 3-174134).
Namely, the cooling device described in the document comprises a housing having a substantially rectangular form with the opposing edge faces opened with a cooling chamber for filling a cooling fluid inside thereof. And of the opposing edge faces, an optical element is provided in one of the edge face sides with the incident-side polarization plate provided in the other edge face side, the opposing open edge faces are closed with the optical modulator and the incident-side polarization plate to form a cooling chamber. With the configuration as described above, heat generated by the light beam irradiated from the light source in the optical modulator as well as in the incident-side polarization plate is directly radiated to the cooling fluid.
In the cooling device described in the document, however, a capacity of the cooling fluid sealed in the cooling chamber is small, the heat exchange capacity with the optical elements such as the heated optical modulator, heated incident-side polarization plate and the like is rather low.
Further as a circulation speed of the cooling fluid sealed within the cooling chamber is low, the cooling fluid is easily warmed up by the heated optical elements, so that a temperature difference between the optical element and the cooling fluid becomes smaller by and by.
Therefore, there is the problem that it is difficult to efficiently cool an optical modulator with a cooling fluid in the cooling device described in the document.